Electrical lighting has become commonplace in modern society. Electrical lighting devices are commonly deployed, for example, in homes and buildings of commercial and other enterprise establishments. Traditional general lighting devices have tended to be relatively dumb, in that they can be turned ON and OFF, and in some cases may be dimmed, usually in response to user activation of a relatively simple input device. Such lighting devices have also been controlled in response to ambient light detectors that turn on a light only when ambient light is at or below a threshold (e.g. as the sun goes down) and in response to occupancy sensors (e.g. to turn on light when a room is occupied and to turn the light off when the room is no longer occupied for some period). Often such devices are controlled individually or as relatively small groups at separate locations. Traditional control algorithms involved setting a condition or parameter of the light output, such as intensity and/or color and then maintaining the set condition within some minimal variance for a relatively long period of time, e.g. over a work day or a period occupancy. Often, the setting(s) would apply to most if not all sources emitting light into a particular illuminated space, for example, so that the illumination throughout the space would have a relatively uniform characteristic.
It has been recognized, however, that variation in lighting characteristics and/or variations over time may have desirable effects on occupants. Simulation of natural lighting, for example, may enhance performance of workers occupying the illuminated space. Other variations may produce adverse effects desired by an operator of the lighting device or system, for example, to encourage people not to linger too long in a particular area. There have been proposals and/or product offerings involving use of video displays as lighting devices mounted on ceilings or walls, where the lighting device displays are driven by image or video signals. In some cases, outside cameras capture video of outside conditions and the lighting devices display the videos to provide indoor illumination.
The Fraunhofer Institute has demonstrated a lighting system using luminous tiles, each having a matrix of red (R), green (G), blue (B) and white (W) light emitting diodes (LEDs) and a diffuser film. The LEDs of the system were driven to simulate or mimic the effects of clouds moving across the sky.
Such display or image simulation type lighting, however, can be distracting as occupants tend to look to the displayed or simulated images, for example, in response to apparent motion in the image.
For these or other reasons, there is room for still further improvement.